drivers: sensors: Implement MAX31875 sensor
This commit implements the temperature sensor interface for the Maxim MAX31875Low-Power I2C Temperature Sensor. Signed-off-by: Pete Dietl <petedietl@gmail.com>
This commit is contained in:
Pete Dietl
Maureen Helm
parent
71707745b2
commit
5dddf9f0f8
8 changed files with 350 additions and 0 deletions
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@ -61,6 +61,7 @@ add_subdirectory_ifdef(CONFIG_LSM9DS0_MFD lsm9ds0_mfd)
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add_subdirectory_ifdef(CONFIG_MAX17055 max17055)
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add_subdirectory_ifdef(CONFIG_MAX17262 max17262)
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add_subdirectory_ifdef(CONFIG_MAX30101 max30101)
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add_subdirectory_ifdef(CONFIG_MAX31875 max31875)
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add_subdirectory_ifdef(CONFIG_MAX44009 max44009)
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add_subdirectory_ifdef(CONFIG_MAX6675 max6675)
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add_subdirectory_ifdef(CONFIG_MCP9808 mcp9808)
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@ -160,6 +160,8 @@ source "drivers/sensor/max17262/Kconfig"
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source "drivers/sensor/max30101/Kconfig"
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source "drivers/sensor/max31875/Kconfig"
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source "drivers/sensor/max44009/Kconfig"
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source "drivers/sensor/max6675/Kconfig"
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5
drivers/sensor/max31875/CMakeLists.txt
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5
drivers/sensor/max31875/CMakeLists.txt
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@ -0,0 +1,5 @@
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# SPDX-License-Identifier: Apache-2.0
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zephyr_library()
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zephyr_library_sources(max31875.c)
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10
drivers/sensor/max31875/Kconfig
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10
drivers/sensor/max31875/Kconfig
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@ -0,0 +1,10 @@
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# MAX31875 temperature sensor configuration options
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# Copyright (c) 2021 Pete Dietl
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# SPDX-License-Identifier: Apache-2.0
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config MAX31875
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bool "MAX31875 Temperature Sensor"
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depends on I2C
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help
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Enable the driver for Maxim MAX31875 Low-Power I2C Temperature Sensors.
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275
drivers/sensor/max31875/max31875.c
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275
drivers/sensor/max31875/max31875.c
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@ -0,0 +1,275 @@
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/*
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* Copyright (c) 2021 Pete Dietl
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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#define DT_DRV_COMPAT maxim_max31875
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#include <device.h>
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#include <drivers/i2c.h>
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#include <sys/byteorder.h>
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#include <sys/util.h>
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#include <kernel.h>
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#include <drivers/sensor.h>
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#include <sys/__assert.h>
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#include <logging/log.h>
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LOG_MODULE_REGISTER(MAX31875, CONFIG_SENSOR_LOG_LEVEL);
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/* Conversions per second */
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#define MAX31875_CONV_PER_SEC_SHIFT 0x01
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#define MAX31875_CONV_PER_SEC_0_25 0x00
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#define MAX31875_CONV_PER_SEC_1 0x01
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#define MAX31875_CONV_PER_SEC_4 0x02
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#define MAX31875_CONV_PER_SEC_8 0x03
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#define MAX31875_CONV_PER_SEC_MASK (BIT_MASK(2) << MAX31875_CONV_PER_SEC_SHIFT)
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/* Data format */
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#define MAX31875_DATA_FORMAT_SHIFT 0x07
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#define MAX31875_DATA_FORMAT_NORMAL 0x00
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#define MAX31875_DATA_FORMAT_EXTENDED 0x01
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/* These are for shifting the data received */
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#define MAX31875_DATA_FORMAT_EXTENDED_SHIFT 0x03
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#define MAX31875_DATA_FORMAT_NORMAL_SHIFT 0x04
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/* Resolution in bits */
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#define MAX31875_RESOLUTION_SHIFT 0x05
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#define MAX31875_RESOLUTION_8_BITS 0x00
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#define MAX31875_RESOLUTION_9_BITS 0x01
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#define MAX31875_RESOLUTION_10_BITS 0x02
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#define MAX31875_RESOLUTION_12_BITS 0x03
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#define MAX31875_TEMP_SCALE 62500
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/**
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* @brief Macro for creating the MAX31875 configuration register value
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*
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* @param mode Data format
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* @param res Resolution (number of bits)
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* @param convs Conversions per second
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*/
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#define MAX31875_CONFIG(format, res, convs) \
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(((format) << (MAX31875_DATA_FORMAT_SHIFT)) | ((res) << (MAX31875_RESOLUTION_SHIFT)) | \
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((convs) << (MAX31875_CONV_PER_SEC_SHIFT)))
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#define MAX31875_REG_TEMPERATURE 0x00
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#define MAX31875_REG_CONFIG 0x01
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struct max31875_data {
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int16_t sample;
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uint16_t config_reg;
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};
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struct max31875_config {
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const struct i2c_dt_spec bus;
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uint8_t conversions_per_second;
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uint8_t data_format;
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uint8_t resolution;
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};
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static int max31875_reg_read(const struct max31875_config *cfg,
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uint8_t reg, uint16_t *val)
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{
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int ret;
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ret = i2c_burst_read_dt(&cfg->bus, reg, (uint8_t *)val, sizeof(*val));
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if (ret < 0) {
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return ret;
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}
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*val = sys_be16_to_cpu(*val);
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return 0;
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}
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static int max31875_reg_write(const struct max31875_config *cfg,
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uint8_t reg, uint16_t val)
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{
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uint16_t val_be = sys_cpu_to_be16(val);
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return i2c_burst_write_dt(&cfg->bus, reg, (uint8_t *)&val_be, 2);
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}
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static uint16_t set_config_flags(struct max31875_data *data, uint16_t mask,
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uint16_t value)
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{
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return (data->config_reg & ~mask) | (value & mask);
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}
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static int max31875_update_config(const struct device *dev, uint16_t mask, uint16_t val)
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{
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int rc;
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const struct max31875_config *cfg = dev->config;
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struct max31875_data *data = dev->data;
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const uint16_t new_val = set_config_flags(data, mask, val);
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rc = max31875_reg_write(cfg, MAX31875_REG_CONFIG, new_val);
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/* don't update if write failed */
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if (rc == 0) {
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data->config_reg = new_val;
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}
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return rc;
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}
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static int max31875_attr_set(const struct device *dev,
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enum sensor_channel chan,
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enum sensor_attribute attr,
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const struct sensor_value *val)
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{
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int ret;
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uint16_t value;
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uint16_t cr;
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if (chan != SENSOR_CHAN_AMBIENT_TEMP) {
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return -ENOTSUP;
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}
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switch (attr) {
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case SENSOR_ATTR_FULL_SCALE:
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/* the sensor supports two ranges -50 to 128 and -50 to 150 */
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/* the value contains the upper limit */
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if (val->val1 == 128) {
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value = MAX31875_DATA_FORMAT_NORMAL << MAX31875_DATA_FORMAT_SHIFT;
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} else if (val->val1 == 150) {
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value = MAX31875_DATA_FORMAT_EXTENDED << MAX31875_DATA_FORMAT_SHIFT;
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} else {
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return -ENOTSUP;
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}
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ret = max31875_update_config(dev, MAX31875_DATA_FORMAT_SHIFT, value);
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if (ret < 0) {
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LOG_ERR("Failed to set attribute!");
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return ret;
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}
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break;
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case SENSOR_ATTR_SAMPLING_FREQUENCY:
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/* conversion rate in mHz */
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cr = val->val1 * 1000 + val->val2 / 1000;
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/* the sensor supports 0.25Hz, 1Hz, 4Hz and 8Hz */
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/* conversion rate */
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switch (cr) {
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case 250:
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value = MAX31875_CONV_PER_SEC_0_25 << MAX31875_CONV_PER_SEC_SHIFT;
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break;
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case 1000:
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value = MAX31875_CONV_PER_SEC_1 << MAX31875_CONV_PER_SEC_SHIFT;
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break;
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case 4000:
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value = MAX31875_CONV_PER_SEC_4 << MAX31875_CONV_PER_SEC_SHIFT;
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break;
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case 8000:
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value = MAX31875_CONV_PER_SEC_8 << MAX31875_CONV_PER_SEC_SHIFT;
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break;
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default:
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return -ENOTSUP;
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}
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ret = max31875_update_config(dev, MAX31875_CONV_PER_SEC_MASK, value);
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if (ret < 0) {
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LOG_ERR("Failed to set attribute!");
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return ret;
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}
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break;
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default:
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return -ENOTSUP;
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}
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return 0;
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}
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static int max31875_sample_fetch(const struct device *dev,
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enum sensor_channel chan)
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{
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struct max31875_data *data = dev->data;
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const struct max31875_config *cfg = dev->config;
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uint16_t val;
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int ret;
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if (chan != SENSOR_CHAN_ALL && chan != SENSOR_CHAN_AMBIENT_TEMP) {
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LOG_ERR("Invalid channel provided");
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return -ENOTSUP;
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}
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ret = max31875_reg_read(cfg, MAX31875_REG_TEMPERATURE, &val);
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if (ret < 0) {
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return ret;
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}
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if (data->config_reg & BIT(MAX31875_DATA_FORMAT_SHIFT)) {
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data->sample = arithmetic_shift_right((int16_t)val,
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MAX31875_DATA_FORMAT_EXTENDED_SHIFT);
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} else {
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data->sample = arithmetic_shift_right((int16_t)val,
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MAX31875_DATA_FORMAT_NORMAL_SHIFT);
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}
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return 0;
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}
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static int max31875_channel_get(const struct device *dev,
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enum sensor_channel chan,
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struct sensor_value *val)
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{
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struct max31875_data *data = dev->data;
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int32_t uval;
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if (chan != SENSOR_CHAN_AMBIENT_TEMP) {
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return -ENOTSUP;
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}
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uval = data->sample * MAX31875_TEMP_SCALE;
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val->val1 = uval / 1000000;
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val->val2 = uval % 1000000;
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return 0;
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}
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static const struct sensor_driver_api max31875_driver_api = {
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.attr_set = max31875_attr_set,
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.sample_fetch = max31875_sample_fetch,
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.channel_get = max31875_channel_get,
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};
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static int max31875_init(const struct device *dev)
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{
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const struct max31875_config *cfg = dev->config;
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struct max31875_data *data = dev->data;
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if (!device_is_ready(cfg->bus.bus)) {
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LOG_ERR("I2C dev %s not ready", cfg->bus.bus->name);
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return -ENODEV;
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}
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data->config_reg = MAX31875_CONFIG(cfg->data_format, cfg->resolution,
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cfg->conversions_per_second);
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return max31875_update_config(dev, 0, 0);
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}
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#define MAX31875_INST(inst) \
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static struct max31875_data max31875_data_##inst; \
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static const struct max31875_config max31875_config_##inst = { \
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.bus = I2C_DT_SPEC_INST_GET(inst), \
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.conversions_per_second = DT_INST_ENUM_IDX(inst, conversions_per_second), \
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.resolution = DT_INST_ENUM_IDX(inst, resolution), \
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.data_format = DT_INST_PROP(inst, extended_mode), \
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}; \
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DEVICE_DT_INST_DEFINE(inst, max31875_init, NULL, &max31875_data_##inst, \
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&max31875_config_##inst, POST_KERNEL, \
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CONFIG_SENSOR_INIT_PRIORITY, &max31875_driver_api);
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DT_INST_FOREACH_STATUS_OKAY(MAX31875_INST)
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50
dts/bindings/sensor/maxim,max31875.yaml
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50
dts/bindings/sensor/maxim,max31875.yaml
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@ -0,0 +1,50 @@
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#
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# Copyright 2022 Pete Dietl <petedietl@gmail.com>
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#
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# SPDX-License-Identifier: Apache-2.0
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#
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description: |
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Maxim MAX31875 Low-Power I2C Temperature Sensor.
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Find the datasheet here:
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https://datasheets.maximintegrated.com/en/ds/MAX31875.pdf
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compatible: "maxim,max31875"
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include: "i2c-device.yaml"
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properties:
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conversions-per-second:
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description: |
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Number of temperature readings performed by the MAX31875 per second.
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0.25 converions per second is the power-on reset configuration.
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type: string
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default: "0.25"
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# Note: the driver relies on the ordering of this enum,
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# so change it with care.
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enum:
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- "0.25"
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- "1"
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- "4"
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- "8"
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extended-mode:
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description: |
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When true, use 13-bit data format to allow for measuring
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temperatures > 128°C
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type: boolean
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resolution:
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description: |
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The number of bits used for each temperature sample.
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A resolution of 10 bits takes 35ms to convert.
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Each 1-bit increase doubles the conversion time.
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Similarly, each 1-bit decrease halves the conversion time.
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10 bits of resolution is the power-on reset configuration.
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type: int
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default: 10
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# Note: the driver relies on the ordering of this enum,
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# so change it with care.
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enum: # Conversion time (ms)
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- 8 # 8.75
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- 9 # 17.5
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- 10 # 35
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- 12 # 140
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@ -725,3 +725,9 @@ test_i2c_ina237: ina237@52 {
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adc-config = <0>;
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rshunt = <0>;
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};
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test_i2c_max31875: max31875@53 {
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compatible = "maxim,max31875";
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label = "MAX31875";
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reg = <0x53>;
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};
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@ -104,3 +104,4 @@ CONFIG_INA23X=y
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CONFIG_INA230=y
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CONFIG_INA237=y
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CONFIG_MHZ19B=y
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CONFIG_MAX31875=y
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